Elevación unilateral de piso de seno maxilar con ventana lateral utilizando xenoinjerto: reporte de caso / Unilateral elevation of maxillary sinus floor with lateral window using xenografts: report of a case

En maxilares atróficos la elevación de piso de seno es una práctica de alta predictibilidad. El adve- nimiento de materiales osteoconductores que generan andamiaje para la formación ósea propor- cionaron un aumento en la tasa de éxito de los implantes endoóseos. El presente artículo reporta un caso clínico en el cual se llevo a cabo un aumento del nivel de altura del piso de seno unila- teralmente por medio de la técnica de Cadwell- Luck modificada por Tatum, técnica con ventana lateral, donde se utilizó xenoinjerto óseo (OstiumMAX, implante de matriz ósea bovina, Laboratorio Bioxen) y membrana reabsorbible de colágeno( Laboratorio Bioxen) en el primer tiempo quirúrgi- co y seis meses después, en el segundo acto quirúrgico se colocaron tres implantes endoóseos (Sistema de implante dental TRP, Laboratorio Tormicron S.R.L.). Los resultados obtenidos fueron controlados en forma mediata y a distancia a través de radiografías panorámicas y tomografías computadas tipo Cone Beam, donde se midió la altura ósea generada post injerto. Pudo consta- tarse el éxito del procedimiento, basándonos en criterios clínico radiograficos de oseointegración (AU)

Boosted selective internal radiation therapy with 90Y-loaded glass microspheres (B-SIRT) for hepatocellular carcinoma patients: a new personalized promising concept.

PURPOSE: To evaluate the impact of dosimetry based on MAA SPECT/CT for the prediction of response, toxicity and survival, and for treatment planning in patients with hepatocellular carcinoma (HCC) treated with (90)Y-loaded glass microspheres (TheraSphere®). METHODS: TheraSphere® was administered to 71 patients with inoperable HCC. MAA SPECT/CT quantitative analysis was used for the calculation of the tumour dose (TD), healthy injected liver dose (HILD), and total injected liver dose. Response was evaluated at 3 months using EASL criteria. Time to progression (TTP) and overall survival (OS) were evaluated using the Kaplan-Meier method. Factors potentially associated with liver toxicity were combined to construct a liver toxicity score (LTS). RESULTS: The response rate was 78.8%. Median TD were 342 Gy for responding lesions and 191 Gy for nonresponding lesions (p < 0.001). With a threshold TD of 205 Gy, MAA SPECT/CT predicted response with a sensitivity of 100% and overall accuracy of 90%. Based on TD and HILD, 17 patients underwent treatment intensification resulting in a good response rate (76.4%), without increased grade III liver toxicity. The median TTP and OS were 5.5 months (2-9.5 months) and 11.5 months (2-31 months), respectively, in patients with TD <205 Gy and 13 months (10-16 months) and 23.2 months (17.5-28.5 months), respectively, in those with TD >205 Gy (p = 0.0015 and not significant). Among patients with portal vein thrombosis (PVT) (n = 33), the median TTP and OS were 4.5 months (2-7 months) and 5 months (2-8 months), respectively, in patients with TD <205 Gy and 10 months (6-15.2 months) and 21.5 months (12-28.5 months), respectively, in those with TD >205 Gy (p = 0.039 and 0.005). The median OS was 24.5 months (18-28.5 months) in PVT patients with TD >205 Gy and good PVT targeting on MAA SPECT/CT. The LTS was able to detect severe liver toxicity (n = 6) with a sensitivity of 83% and overall accuracy of 97%. CONCLUSION: Dosimetry based on MAA SPECT/CT was able to accurately predict response and survival in patients treated with glass microspheres. This method can be used to adapt the injected activity without increasing liver toxicity, thus defining a new concept of boosted selective internal radiation therapy (B-SIRT). This new concept and LTS enable fully personalized treatment planning with glass microspheres to be achieved.

Safe radiation exposure of medical personnel by using simple methods of radioprotection while administering 131I-lipiodol therapy for hepatocellular carcinoma.

The intra-arterial administration of 131I-lipiodol is a therapeutic approach increasingly used for the treatment of inoperable hepatocellular carcinomas. This technique has even become the reference treatment for hepatocellular carcinomas with portal thrombosis and is the only effective treatment to reduce the risk of recurrence among patients who could benefit from surgical operation. Currently, few data have been published concerning the levels of exposure for personnel carrying out this type of treatment. We undertook a dosimetric study targeted mainly on the exposure of the person performing the injection of 131I-lipiodol to show that this treatment can be carried out with an exposure at the extremities distinctly lower than the regulatory annual threshold by using simple means of radioprotection. The point of puncture was carried out at the level of left femoral artery, the preparation and injection of the therapeutic dose was carried out extemporaneously by the nuclear medicine specialist using a 10 ml syringe (for an injected volume of 4 ml) fitted with an adapted syringe protector. The injection was carried out as rapidly as possible under scopic control while avoiding reflux, with compression carried out by the radiologist. This study comprises 52 intra-arterial injections of 131I-lipiodol (2016+/-92 MBq). For the nuclear medicine specialists, 52 measurements were carried out at the level of the thorax and 41 on the fingers. For the radiologists, 22 measurements were carried out at the level of the thorax and six on their index fingers; nine measurements were carried out at the level of the thorax for the technologist and four at the level of the thorax for the stretcher bearer. For the nuclear medicine specialists, the average dose received at the level of the fingers varies between 140 and 443 microSv (according to the fingers) and the average dose at the thorax is 17 microSv. For the radiologists, the average dose received is 215 microSv at the level of the fingers and 15 microSv at the thorax. These results show that the administration of high therapeutic activities of 131I-lipiodol can be carried out for the exposed personnel with a dose at the level of the fingers much lower than the European regulatory limit of 500 mSv.

Scintimammography: better detection of small-sized lesions with tomoscintigraphic than planar images, a phantom study.

Planar (99)Tc(m)-methoxyisobutylisonitrile ((99)Tc(m)-MIBI) scintimammography has been used for several years to detect breast cancer tumours, but with low sensitivity for small lesions. Results of tomoscintimammography studies have not been conclusive. We conducted a phantom study to compare the detection of small-sized tumours with planar versus tomoscintigraphic images. We used a data spectrum anthropomorphic fillable breast phantom with two 9.8 mm and 12.4 mm spheres superficially or deep in the breast compartment with sphere/breast activity ratios varying from 3 to 6. We acquired planar and 180 degrees tomoscintigraphic images in each configuration using a double head standard gamma camera. In certain cases we varied different parameters (64x64 matrix or 360 degrees rotation) in a second series of tomoscintigraphic acquisitions. We simultaneously used filtered back-projection reconstruction (FBP) and iterative reconstruction (IR). Planar images were shown by the sphere in 10 out of 25 cases. Tomoscintigraphic images were shown by the sphere in nine out of 25 cases with FBP and in 18 out of 25 with IR. There was a significant difference between IR and FBP (P<0.01) and between planar and IR images (P<0.01), but no significant difference between planar and IR images. The noise/signal ratio was lower with planar images than with the two types of reconstruction (P<0.05) but was not significantly different between the two types of reconstruction. Contrast was lower on planar images than on the two types of reconstruction (P<0.05) and was also better on IR than on FBP images (P<0.05). Granularity was lower for planar images than for reconstruction images (P<0.01) and also lower for IR than for FBP (P<0.01). The tomoscintigraphic reconstructions acquired with a 64x64 matrix were only positive in four out of 10 cases, while they were positive in nine out of 10 with a 128x128 matrix. We concluded that, in this phantom study, tomoscintimammography with IR provides a significant improvement in the detection of small-sized breast tumours compared with planar images. In addition, for tomoscintigraphic images, a 128x128 matrix is preferable to a 64x64 matrix. Those results have, of course, to be confirmed in vivo in a large population of patients with small-sized breast lesions.

Importance of the choice of the collimator for the detection of small lesions in scintimammography: a phantom study.

99mTc methoxyisobutylisonitrile planar scintimammography (SMM) is mostly performed using low-energy high-resolution (LEHR) parallel collimators. We studied whether using a different collimator could improve the detection of small (< 1.5 cm) lesions for which SMM sensitivity is poor. Thirty four breast phantom configurations were considered, either with hot spheres simulating lesions or without any spheres. For each configuration, four planar acquisitions were performed using LEHR, low-energy ultra high-resolution (LEUHR), high-resolution fan-beam (HRFB) and ultra high-resolution fan-beam (UHRFB) collimators. Images corresponding to the 20% and 10% energy windows and to the Jaszczak subtraction were calculated. A database including 156 borderline images was derived. After training, 10 observers scored the images for the presence of a sphere. The performances in sphere detection were studied using receiver operating characteristic (ROC) analysis. For all types of image, the area under the ROC curve was highest with the UHRFB collimator and lowest with either the LEUHR or the HRFB collimator. For the 10% energy window images conventionally used in SMM, the detection sensitivities averaged 91%, 73%, 60% and 55% for the UHRFB, LEHR, HRFB and LEUHR collimators respectively, for the same specificity of 64%. We conclude that detection of small tumours in planar SMM might be significantly improved by using a UHRFB collimator instead of an LEHR collimator.

Decreased oxyhemoglobin affinity in patients with sleep apnea syndrome.

Oxyhemogloblin affinity (P50 at pH 7.4, PaCO2 = 40 mm Hg, temperature = 37 degrees C) and 2,3-DPG concentration were assessed in 15 nonsmokers (14 men and one woman 46 to 63 yr of age) with sleep apnea syndrome (SAS) and in 10 normal subjects (eight men and two women 22 to 48 yr of age). In patients with SAS, mean nocturnal apnea index was 46 +/- 20/h, and mean nocturnal SO2 was 86 +/- 6% versus 94.6 +/- 1.8% during the daytime. Daytime mean P50 of the patients was 28.5 +/- 1.2 mm Hg versus 27.1 +/- 0.3 mm Hg in the normal subjects (p less than 0.05). Daytime mean 2.3-DPG was 1.23 +/- 0.25 moles DPG/mole hemoglobin versus 0.80 +/- 0.15 (p less than 0.05). Significant correlations were found in patients between P50 and mean nocturnal SO2 (r = -0.62, p less than 0.01) and between P50 and 2,3-DPG (r = 0.68, p less than 0.01). The measurements were repeated in five patients after surgical or positive-pressure treatment. P50 and 2,3-DPG both decreased and returned to normal values. In conclusion, the oxyhemoglobin dissociation curve is shifted to the right in patients with SAS and there is an increase in 2,3-DPG. These could be protective mechanisms against the development of polycythemia, pulmonary hypertension, and cor pulmonale.